Cloud storage company Box has always differentiated itself from competitors like Dropbox, Microsoft OneDrive, and Google Drive with its strong focus on helping developers build things f on top of its service.

"This is where we're seeing business models emerge," said Box CEO Aaron Levie on stage at the company's BoxDev event in San Francisco.

To that end, Box today announced a $40 million fund for startups who are building their companies on top of the Box service, in partnership with Bessemer Venture Partners and Emergence Capital Partners.

If Box wants to rule the business software market, it needs a lot of people using it. To get a lot of people using it, it needs apps that use it as the storage service on the backend. To get apps that use the service, it needs more startups willing to do it.

And while a big company like SAP is never, ever going to do that, new apps from new startups have a huge opportunity — just look at the success of new enterprise software like Slack and Domo (the latter of which, incidentally, is apparently a Box customer).

For Bessemer and Emergence, it's a matter of joining the winning team. As software continues to eat the world, they want to invest in startups that are using Box to quickly and efficiently build out their offerings so they can focus on making the features that set them apart.

Bessemer partner Byron Deeter described Box's platform as "the best that's out there," and that there's "no need to reinvent the wheel."

Emergence partner Jason Green agreed, saying that when it came to investing in enterprise startups, "I'd much rather be investing in companies solving feature problems."